The source of that particular quote was a Facebook post by someone named Jessica Dovey:
> @pennjillette I am the original author of the "MLK" quote. Somewhere my words got mixed with his. The post:
Dovey said "I mourn the loss of thousands of precious lives, but I will not rejoice in the death of one, not even an enemy", and then quoted Martin Luther King Jr.:
> "Returning hate for hate multiplies hate, adding deeper darkness to a night already devoid of stars. Darkness cannot drive out darkness: only light can do that. Hate cannot drive out hate: only love can do that." \- Martin Luther King, Jr.
The Facebook post itself appeared as follows:
!How the quote got mixed up